Human movement monitoring provides a way to quantitatively assess function without therapist intervention. Knowledge of how individuals use their affected limbs as they interact in an unsupervised environment, such as the home, is critical to evaluating motor function and recovery following an injury or a neurologic event. Moreover, an accurate assessment of movement at home is important to administering appropriate therapy in the clinic and to developing appropriate rehabilitation interventions. Home monitoring also enables the possibility to provide daily quantitative assessment to the user, which can help motivate use of the affected limb.
Questionnaires are commonly used to assess the functionality of upper and lower extremities but provide only a subjective interpretation, which can lead to inconsistent assessment results. Recent advancement of miniaturized electronics and sensors has brought about a surge of devices for at home, unrestrained human monitoring that can quantitatively measure use. Accelerometer-based systems are the most common modality for measuring lower-extremity and upper-extremity movement. Although these systems can be used to estimate the amount of gross movement of the upper extremity, they do not address movement quality and small movements may not be detected. Moreover, because the sensors are worn on the wrist, accelerometry is insensitive to fine movements of the wrist and hand, such as those made when writing or typing.
In the laboratory, sophisticated data gloves, goniometers, and motion-capture systems can be used to quantify use of the wrist and hand. However, such devices are not designed for long-term data logging in an uncontrolled environment. In addition, such devices can be difficult for individuals with a physical impairment to don and doff, may restrict natural movement of the hand, and may be too cumbersome to wear for long periods of time.
In view of the above discussion, it can be appreciated that it would be desirable to have an alternative way to measure specific hand or wrist movements in uncontrolled settings.